Screen stencil machine with traveling orbital inker



N. LOUFT SCREEN STENCIL MACHINE WITH TRAVELLING ORBITAL INKER Filed April 7, 1944 3 Sheets-Sheet 1 [ave/p for w w- May 27, 1947. N. LOUFT 2,421,210

SCREEN STENCIL MACHINE WITH. TRAVELLING ORBITAL INKER Filed April 7. 1944 3 Sheets-Sheet 2 N. LOUFT May 27, 1947.

SCREEN STENCIL MACHINE WITH TRAVELLING ORBITAL INKER Filed Apri1 7, 1944' 3 Sheets-Sheet 25 Patented May 27, 1947 UNITED STATES PATENT OFFICE I SCREEN STENCIL MACHINE WITH TRAVELING ORBITAL INKER Nathan Louft, Silver Spring, Md.

Application April 7, 1944, Serial No. 530,007

1 12 Claims.

This invention relates to the ofllcial class of printing and more particularly a stencil printing machine. 7

The primary object of this invention resides in the provision of a stencil printing machine, of the screen process printing character, wherewith production over the manual practice of so printing will be materially increased.

Another object of this invention reside in the provision of a stencil printing machine, oi. the screen process printing character, which can be readily operated by an individual having experience in the manually operated screen process printing art.

A further object of this invention resides in the provision of a stencil printing machine, of the screen process printing character, which is simple in construction and emcient in operation.

A still further object of this invention resides in the provision of a stencil printing machine, of the screen process printing character, which will produce high quality work with spoilage of stock or waste of printing material reduced to the minimum.

Aside from the aforesaid objects, this inven tion resides in the provision of a stencil printing machine of such simple construction and arrangement of elements that positive cooperation of the moving element is assured at all times.

In addition to the foregoing objects, this invention resides in the particular construction and operation of the squeegee.

Among the many objects of this invention is the provision of a stencil printing machine of such construction that stock to be printed can be fed thereto from either side or front thereof.

One of the salient features of this invention resides in the particular construction and operation of the studs for registering stock relative to the printing screen.

Included among the salient features of this invention is the printing screen retaining and manipulating means.

Another important object of this invention resides in the provision of printing screen retaining and manipulating means of such construction that theusual heavy screen carrying frame heretofore employed is eliminated to greatly reduce the number of moving parts in conventional machines.

With these and other objects in view, this invention resides in certain novel features of construction and arrangement of elements to be hereinafter more particularly set forth in the specification, illustrated in the accompanying drawings and pointed out in the appended claims and, while this disclosure depicts my present conception of the invention, the right is reserved to resort to such changes in construction and arrangement of elements as come within the spirit of the invention.

In the accompanying drawing forming a part of this application;

Fig. 1 is a side view of a stencil printing machine, of the screen printing process character, constructed in accordance with this invention.

Fig. 2 is a plan view thereof.

Fig. 3 is a detail perspective view of a portion of the squeegee and its companion elements.

Fig. 4 is a similar view of a portion of one side of the frame showing the entrance end of the track secured thereto.

Fig. 5 is an enlarged sectional view taken approximately on line 5-5 of Fig. 2.

Fig. 6 is-a detail cross sectional view taken approximately on line 6-6 of Fig. 2.

Fig. 7 is a diagrammatic view showing amodifled form of driving the conveyor chains of the squeegee.

Fig. 8 is a detail longitudinal sectional view of a portion of the screen showing the paint guard secured to the frame thereof.

Fig. 9 is an enlarged longitudinal sectional view takenapproximately on line 9-'9 of Fig. 2. In the present illustration of this invention the numeral 5 designates, in general, a stencil printing machine, of the screen printing process character, consisting of a frame 6 herein shown as supported by legs 1 which are retained in rigid relation by braces 8.

Secured to the frame 6 and having certain areas 9 of its front portion In extending through elongated open slots ll formed in upstanding side members i2 and carried by the frame is a bedplate l3, having a series of apertures N therethrough to slidably receive guide-pins l5 to be hereinafter more definitely described. Disposed on or formed integral with the side members 12 adjacent their front and rear ends are suitable bearings 15 in which is joumalled stub-shafts i6 and I1 carrying longitudinal aligned sets of sprockets l8 and I9 over which conveyor chains 2il2| are trained to travel in parallelism on opposite sides of the machine and at a common rate of speed transmitted thereto through the instrumentality of sprockets 22 and 23 connected by chain 24 and 25 to sprockets 26 and 2'! On a counter-shaft 28 which in turn is 3 driven by a motor 29 transmitting its power thereto through a suitable clutch 3| and power transmitting means 3| and, in order to disconnect the motor from the driving elements of the conveyors and thus stop the same, a clutch pedal 32 or other suitable element is connected to the clutch and disposed in convenientreach of the operator. The clutch in the instant case is of the type whereby the operatorean absent himself from the machine without stopping the motor.

While the aforesaid driving means successfully operates the machine in quantity and quality production, it is within the purview of this invention to substitute other power transmitting means for the conveyors just so the gist of the invention is not departed from.

Pivotally connected as by hinges 3! to the bed plate I3, preferably at its rear end, is a substantially U-shape clamp 34 provided with suitable fastening elements 35 between which a portion, preferably the rear member. of a conventional printing, screen 36 is secured for adjustment in accordance to the thickness of the stock to be printed and desired contact therewith. I

Connected to the aforesaid ll-shape clamp 34, preferably through the instrumentality of an arm 31 extending rearwardly therefrom, is one end of a retractile spring 38 which has its opposite end connected to a stationary portion of the machine, herein shown in the form of a brace or cross-bar 39.

Secured to the arm 31 or other suitable part of the U-shape clamp is a 'slotted standard "supporting a paint-guard ll through the instrumentality of adjustment means herein shown in the form of a slotted arm42 secured to said paint-guard and connected to said standard by a fastening element 43 passing through the slots in said elements. In that form of the screen shown in Fig. 8 of the drawings, the paint guard II is secured to the frame thereof for 'co-operation with the squeegee in the manner heretofore set forth.

Pivotally connected to the lower surface of the bed-plate by a suitable pivot 44 is a lever 45 which in turn is suitably connected to the aforesaid stock guide-pins l and an arm 46 secured to the U-shape clamp and. in order to adjust the lever 45 on the arm 46 to control the movement of the pins IS, a fastening element 41 passes through registering slots 48 and 49 in said elements.

Through the instrumentality of the aforesaid retractile spring 38 and U-clamp the screen will be rocked on the pivot 33 to its normal or elevated position against a stop 5|,herein shown in the form of a removable bar supported by the side members l2 and, in order to obviate jar or sudden stoppage thereof when approaching or completing its upward movement, a suitable cushioning element 5| is connected to the U- clamp and a stationary portion of the frame, the same in the instant case being of the conventional pneumatic type whereby air is expelled gradually from a cylinder having a piston therein.

The squeegee heretofore mentioned is formed of an elongated piece of rubber or other suitable material secured between a paint trough 52 disposed against its front surface and an elongated plate 53 disposed against its rear surface and, to facilitate adjustment of the aforesaid elements relative to a cross-bar 5i connecting the same to conveyor chains, guide blocks 55 are formed on the plate 53 and have apertures 56 therein for slidable engagement with studs 51 secured to the cross-bar 54. In order to retain the squeegee and trough in adjusted position on the studs 51, set-screws 58 are threaded into the guide blocks 55.

Formed on or otherwise secured to the inner surfaces of the side members I! are upper and lower guide rails 59 and ill between which the opposite ends SI of the cross-bar 54 slide during the operational cycle of the squeegee in forcing paint through the screen, said guides acting to cause proper presure of the squeegee against the screen and also to cause it to traverse the screen smoothly.

Disposed over the conveyor chains are safety guards 62.

In order to prevent paint from accumulating against the front members 63 of the. screen frame, bevel strip 64 is secured across the screen and against said front members.

Carried by the cross-bar 54 in alignment with side members 65 of the screen frame are shoes 66 adapted to contact said side members at certain points during the inactive cycle of the squeegee and thereafter depress the screen toward the stock to be printed so it will oppose the stock and remain in printing position thereover while the squeegee presses the paint through the screen and, upon the squeegee reaching the end of its active stroke on the screen it will engage the paint guard M during its upward movement sheet of stock on the bed-plate and against the guide-pins so as to register the stock beneath the printing screen and upon contact of the continuously moving shoe on the squeegee supporting bar which is connected to the conveyor chains, the frame will be depressed and held against the stock by the shoes during that period the squeegee traverses the screen with the paint thereon and subsequently thereto the point guard will transfer the surplus paint from the squeegee to the paint trough or cup to be used during the succeeding operational cycles of printing.

In the modified form of the conveyors shown in Fig. '7 of the drawings, the sprockets 19 are splined on a common shaft 10 which in turn is connected to the counter-shaft by a single chain ll trained over sprockets I2 and 13, thus it is apparent the conveyors and other operating elements heretofore set forth are synchronized to permit practice of the art of printing by the screen printing process.

With this invention fullyset forth, it is manifest that means are provided whereby an artisan familiar with printing under the screen process method will readily acquire full knowledge of operating the machine and, through the simplicity of the mechanism embodied therein, positive operation of the same is ensured so as to materially produce quantity and quality production.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. A printing machine of the character set forth, the combination of, a bed-plate, endless conveyors mounted thereover in space parallel relation, a clamp pivotally secured to the bedplate, a printing screen carried by the clamp and operable between the conveyors, means yieldingly retaining the clamp and printing screen in inclined elevated position at one end, a squeegee connected to said conveyors, a paint trough connected to said conveyors and disposed adjacent the squeegee, stock guide-pins slidably extending through the bed-plate, shoes connected to the conveyors in alignment with the inclined sides of the screen, a frame supporting the bed-plate, side members on the frame, squeegee guide rails on the side members, a paint-guard in the path of the squeegee at a point beyond its working cycle on the screen, means securing the paintguard to the clamp, means connecting the stock guide-pins to the clamp, cushioning means connected to the clamp, and power transmitting means including a clutch connected to the conveyors.

2. A printing machine of the character set forth, the combination of, a frame, means rigidly supporting the frame and having longitudinally extended open slots formed in their front portions, a. bed-plate supported by the frame and having portions of its sides extending through said slots in the side members, stock guidepins extending through the bed-plate, bearings mounted on the side members, stub-shafts journalled in said bearings, sprockets carried by said stub-shafts, endless conveyor chains trained over said sprockets, a cross-bar secured to the conveyor chains, an elongated plate adiustably mounted on the cross-bar, means securing the plate in adjusted position on the cross-bar, a squeegee disposed against one side of the plate, a paint trough disposed against the squeegee, means securing the squeegee between the plate and paint trough with its working portion extending outwardly of the mouthof the trough and plate, guide-rails on the inner opposed surfaces of the frame to receive the free ends of the aforesaid cross-bar therebetween during the working cycle of the squeegee, a printing screen, means pivotally and yieldingly supporting the printing screen in inclined relation to the aforesaid bed-plate, cushioning means connected to the screen supporting means, means connecting the stock guide-pins to the screen supporting means whereby the gauge-pins will move below the surface of the bed-plate prior to the printing screen contacting the stock to be printed, shoes on the cross-bar depressing the printing screen and retaining it against the stock to be printed while the squeegee presses the paint therethrough, a paint guard in the path of the squeegee and adjacent its working operational path on the screen, means adjustably securing the paint-guard to the screen supporting means, and power transmitting means including a clutch connected to certain of the stub-shafts. I

3. A printing machine of the character set forth, the combination of, a bed-plate, a support for the bed-plate, a printing screen pivotally disposed over the bed-plate in inclined relation squeegee and operable by the conveyors, shoes adjacent opposite ends of the squeegee and o erable by the conveyors over certain portions of the printing screen, stock guide-pins slidably extending through the bed-plate, means yieldingly retaining the printing screen in normal inclined relation to the bed-plate, means synchronizing operation of the stock guide-pins with the movement of the printing screen, a paint-guard disposed in the path of the squeegee and adjacent the end of its workin cycle over the printing screen, means supporting the paint-guard for rocking movement with the printing screen, cushioning means controlling the printing screen in its upward movement, and power transmitting means connected to the conveyors.

4. A printing machine of the character set forth, the combination of, a frame having side members provided with elongated slots open at the front ends thereof, a bed-plate supported on said frame and having certain areas thereof extending through said-slots and beyond the side members of the frame, an inclined printing screen pivoted adjacent the rear end of the bedplate and operable thereover, a squeegee, a paint receptacle secured to the squeegee, means conveying the squeegee and paint receptacle over the screen in both its printing and inactive strokes. and means travelling with the squeegee and paint receptacle depressing the screen and retaining it in printing position to accommodate the squeegee while pressing paint therethrough, means for removing the residue paint from the squeegee subsequent to completing its paint pressing operation and depositing it in the recptacle for subsequent use, and power transmitting means connected to the squeegee conveying means.

5. A machine of the character set forth, the

combination of, a frame, side members on the frame provided with elongated slots open at their front ends, a bed-plate secured on the frame and having certain areas thereof extending,

through the slots and beyond the side members, a printing screen operable to and from the bedplate, yielding means retaining the printing screen in raised position at its front end, guidepins of different lengths slidably disposed through the bed-plates, a squeegee, means conveying the squeegee in contact with and over the screen, means depressing and holding the screen down against the stock to be printed, a lever pivotally connected to the bottom surface of the bed-plate extending diagonally downward therefrom and pivotally supporting the guidepins with its outer end connected to the screen retaining means and power transmitting means connected to the squeegee conveying means.

6. A machine of the character set forth, the combination of, a frame, a support therefor, side members connected to the frame and having longitudinally extending open slots in their front portions, a bed-plate having certain areas of its front portion extending through the slots and outwardly of the side members, a printing screendisposed over the bed-plate, pivotal means connected to the printing screen, yielding means thereto, parallel conveyors mounted on the support of the bed-plate on opposite sides of the printing screen, a squeegee connected to the conveyors and operable over the printing screen, a paint trough disposed against one side of the retaining the screen in elevated position, conveyor chains mounted on the side members outwardly of the printing screen, a squeegee, a paint receptacle, shoes disposed in alignment with the sides of the screen, frame means supporting and connecting the squeegee, paint receptacle and shoes to the conveyors, means removing residue paint from the squeegee subsequent to its active stroke over the screen and depositing it into the paint receptacle, cushioning means connected to the screen, pivotal means and power transmitting means including a clutch and pedal therefor mounted on the frame support and connected to the squeegee operating means.

'7. A squeegee comprising a support, upstanding pins secured to the support, an inclined plate,

apertured blocks secured to the plate and slidably disposed on the pins, set-screws threaded into the blocks and engaging the pins, a paint trough, a strip of rubber disposed between the trough andsaid plate with its free-edge disposed beyond the edge of the trough, and fastening elements securing the trough and rubber strip to the plate.

8. The combination with a printing screen, a substantially U-shape clamp loosely receiving one end of the printing screen, clamping screws engaging the screen from opposite sides, and means pivotally securing the clamp to a Portion of the printing machine.

9. The combination with a printing machine of the character set forth, a bed-plate, a printing screen, means loosely receiving a portion of and rockably supporting. the printing screen from one end, means adjustably securing the screen to the receiving means thereof, guide-pins slidably extending through the bed-plate, and means connecting th guide-pins to the screen supporting means for retracting the same when the screen rocks to working position over stock tobe printed.

10, The combination of a printing machine of the character set forth, a1 substantially U- shape clamp pivoted to the machine, a printing screen of lesser thickness than the clamphaving a portion thereof disposed between the arms of the clamp, and adjustable fastening elements bearing on opposite sides of the screen to regulate it relative to theclamp.

Number 11. A printing machine of the character set forth, the combination of, a bed-plate, a screen movable over the bed-plate, synchronized endless conveyors on each side of the bed-plate, and a squeegee including screen engaging means connected to the conveyors for gradually lowering the screen and printing therethrough.

12. A printing machine of the character set forth, the combination of a bed-plate, a screen movable over the bed-plate toward and from the same, synchronized endless conveyors mounted adjacent the sides of the screen, a squeegee con nected to the conveyors gradually depressing and thereafter traversing the screen, and means simultaneously disposing the squeegee and screen in printing relation.

NATHAN LOUFI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

